Wall for marine vessels



May 22, 1945. E SOMES 2,376,517

' WALL FOR MARINE VESSELS Filed Dec. 8, 1943 a HARDENED SIDE *5 JNVEN'I'OR i'lbward E. Sam/es,

ATTORNEY cam: an m, 1945 U ITED STATES PATENT OFFICE WALL FOB. MARINE VESSELS Howard E. Source, Detroit, Mich, asolgnor to Budd Induction Heating, Inc., Philadelphia, Pa., a corporation of Michigan Application December 8, 194:, Serial No. 513,366

2 Claims.

invention relates .to'improvements in the art of ship construction, more particularly to the construction of submarines and that portion of the hull of a surface vessel which is subject to collapse incident to the pressure of the water.

An object oi the. present invention is to provide a metallic structure which is particularly adapted for use in the hull structure of a surface vessel or submarine, constructed and arranged to provide for great resistance to collapse incident to water pressure, and, at the same time to cheat a reduction in weight and, therefore, the cost of the metal used in such structures.

with the above and other objects in view, which will be apparent from the following detailed description to those skilled in the art to which the invention appertains, the present invention consists in certain features of construction and procedure to be hereinafter described, with references to the accompanying drawing, and then claimed.

In the dra:

Fig. 1 is a transverse section through a hollow structure, the walls of which are comprised of metallic plates, as in a submarine or surface vessel.

Fig. 2 is a section through plate stock used for producing a ship plate in accordance with the present invenfion; v

3 is a similar section in which additional cross-hatching indicates'a hardened zone, the broken outline indicating the shape assumed by the plate incident to stresses produced as a result of the hardening operation; and

Fig. 4 is a diagrammatic view showing a hardened plate in the process of being rolled to shape.

In the illustrated embodiment of Fig. l, the hollow structure is comprised of a series of plates It joined together by means of overlapping plates ii riveted thereto. However, any other suitable means or connection may be employed.

Each of the plates 10 is heat treated and quenched, preferably in accordance with the method disclosed in my Patent No. 2,288,033, granted June 30, 1942, by means of which there is established at one side of the plate a hardened layer or zone I! and for the remainder of the thickness of the metal a relatively u'nhardened or less hcrdlayer ii zone 13. Although only marked in mg. 1 Hardened Side, the hardened layer or zone i2 is located at the convex side of the plate W in its assembled form (see Fig. 4)

According to the method disclosed in my patent aforesaid, thehardness and the depth of hardnose of the layer in questioncan be accurately controlled with the result that the relative yield strengths of the hardened and unhardened layers also can be closely controlled.

Through the use of heating rapidly by inductionheating followed by substantially immediate quenching, as disclosed in my patent aforesaid, there not only is a sharp line of demarcation between the two layers of metal as respects their hardness, [but also,'there is a predetermined inherent stress relation set up. With the proper proportioning of the-depth of the hardened layer with respect to the thickness of the metal, the hardened layer is placed under a stress condition of residual compression whereas the unhardened layer is placed under a stress condition of residual tension. It has been ascertained in a hollow metal body that if the metal adjacent the concave side is under a state of residual compression in an unloaded condition, such body will be materially more resistant to collapse incident to externally applied forces than when free from the residual stress condition described. This residual stress condition is thus used to greatadvantage in the present invention.

A metal plate, such as the plate it, when subjeeted to the heating and quenching operation described to provide the hardened layer it, indicated in Fig. 3, will tend to relieve itself of the residual stresses by distorting to the shape shown in broken outline in Fig. 3. Here it will be seen that the hardened layer is at the convex side of the plate.

In order that the inherent compression characteristics of'the hardened layer may be retained and utilized to advantage in ship hull construction, the plate it, so hardened, is subjected to a rolling actionas indicated in Fig. 4, which rolling action is carried to such point as to stress the unhardened layer beyond its elastic limit, thus upsetting this layer. 'The depths of the two layers are'predetermined to such degree that during the and assembled into a hull of substantially continucus curvature, as in the case of a submarine, the result, with the proper proportioning of the dimensional and physical factors, will be a struc- A further feature ofthe present invention is that, it desirable, the plate may first be hardened throughout its depth and then drawn back to any desired point to regulate the hardness ultimately to such degree as might be desired to render the .plate more risistant to piercing by Shells or the like. Thereafter, the plate, the main body of which has had its hardness adjusted, is then treated in accordance with the process described to create hard and less hard inner and outer layers respectively, but in which the hardness of the outer layer is greater than it would be in the absence of the initial operation-of hardening the plate throughout its thickness.

The method of producing the plates of the present invention forms the subject matter of and is claimed in my copending divisional application, Serial No. 546,528, filed July 25, 1944.

Various changes may be made in the features and procedure described without departing lrom the spirit of the present invention, the scope 01' which is defined by the appended claims.

Whatisclaimedis:

1. In a hollow hull or body structure of ships, submarines and the like, having curved metallic plates subject in use to external pressure, means for increasing the normal resistance of said plates to collapse incident to external pressure, comprising for at least some of said plates a layer of metal at the concave side thereof of greater hardness than the remainder metal, the metal of said layer in the absence of pressure externally oi the plates being under a state of elastic compression.

2. In a hollow hull or body structure for ships, submarines and the like, a plurality of interconnected curved metallic plates therefor, the convex surfaces of said plates, being subject in use to collapse incident to pressures acting against said convex surfaces, at least certain of said plates having the hardness of the metal at the concave side thereof and for a predetermined depth greater than the hardness of the remainder of the metal, the harder metal being, in the absence of pressure externally of the structure, under a state of elastic compression.

HOWARD E. BOMES. 

